The invention relates to a cross-country ski binding of the type with a boot sole extended forwardly by way of a flexible zone and with a retaining element fixing the boot sole extension against longitudinal displacement in the in-use condition. Ski bindings of this type have been contemplated with a guide arm and/or a pair of such guide arms, forming together with the retaining element a toggle lever, this guide arm or these guide arms guiding the retaining element, which shifts forwardly due to pressure from above against the spring action of a tension spring, from a lifted release position into a lowered in-use position, wherein the retaining element secures the sole extension in place in the forward direction, by extending behind a projection or a corresponding part at the boot sole extension and by traversing a dead-center position with respect to the tension spring between the release position and the in-use position.
By using a guide arm or a pair of guide arms in such a binding, it is possible to attain a particularly reliable guidance and a forwardly pulling tightening of the retaining element. A tension spring, fashioned as a draw spring, secures the retaining element in its two rest positions on both sides of its dead-center position.
A primary object of the invention is to simplify a binding of the aforementioned type, particularly with respect to the spring system required for bracing the boot sole extension by means of the retaining element. The invention, accordingly, resides in the provision that one of the three joints of the toggle lever is resiliently supported or fashioned to be resilient in the longitudinal direction of the ski with respect to the latter and/or to the boot sole. This eliminates the need for a separate tension spring, which normally can be included in the binding arrangement in the form of a draw spring only under difficulties.
The resilient support or resilient construction of the respective joint can be effected in various ways according to the respective different preferred embodiments of the invention. In one embodiment of the invention, the guide arm has resilient play in the longitudinal direction with respect to the retaining element and/or with respect to the binding part fixedly attached to the ski. A spring can be supported, in this arrangement, preferably on a hinge pin connecting the retaining element to the guide arm, whereby the retaining element is urged forwardly in the longitudinal direction of the ski by the spring.
In another particularly simple embodiment of the invention, the guide arm proper is fashioned to be resilient in its longitudinal extension, and advantageously formed as a bracket.
In another embodiment of the invention, an abutment is provided for the spring, which spring is supported fixedly on the ski at its other end, the abutment being arranged on the ski or on a binding or bearing member affixed to the ski so that it is movable toward the rear in the longitudinal direction of the ski, the arrangement being such that the movable abutment, in the in-use position, contacts the boot sole extension under the action of the spring and presses the extension against a hook-shaped counter projection at the retaining element, this counter projection forming an effective third joint (pivot) of the toggle lever and extending behind a projection at the sole extension.
In another, especially simple embodiment of the invention, the projection at the sole extension, behind which the retaining element extends, is fashioned to be resilient, whereas the guide arm and the retaining element are fashioned to be rigid or essentially rigid or are supported against each other.
Other contemplated arrangements for producing a resilient effect securing the retaining element and thus the boot sole extension in position resides in constructing one of the joints of the guide arms to be resilient. For this purpose, it is contemplated, in particular, to embed the hinge pin of the resiliently fashioned joint in a cushion of an elastic material, such as rubber or the like. Also, the hinge pin of the resiliently fashioned joint is constructed to be flexurally elastic so that it bends resiliently under the effect of the tensile forces generated at the binding according to yet further contemplated embodiments.
The guide arms, forming a toggle lever together with the retaining element, as well as the springs can be arranged singly or in pairs, for example on both sides of the longitudinal axis of the binding or of the ski according to respective different contemplated preferred embodiments. In all of the preferred illustrated embodiments, a pair of guide arm toggle lever arrangements are provided at opposite sides of the ski binding longitudinal centerline with resultant reliable and stable holding of a ski boot toe extension. However, the mentioning of a guide means or some other part of the toggle lever or any other part associated therewith in the claims also contemplates inclusion of these parts in pairs, as well as on a single arrangement unless otherwise specifically set forth.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.